This invention relates to the field of analytical instruments. More specifically, it relates to the field of instruments for testing underground storage tanks or other inaccessible tanks for leaks. Recent government regulations have required the detection and correction of relatively minor leaks in underground storage tanks which contain various chemicals, such as gasoline, kerosine, diesel fuel and the like. This is in order to prevent the contamination of ground water or the soil. The regulations require the detection and correction of minute leaks on the order of 0.05 gallons per hour.
In the case of underground tanks, it is not possible, of course, to visually inspect the tanks for leaks and it is relatively expensive to repair the tanks in the event of a leak. Accordingly, there is a need to know whether or not such tank is leaking and, if so, the extent of the leak in order that an informed judgment may be made concerning the need to service the tank.
Tank testing systems for underground tanks are known in the art. Perhaps the most well known system is the Kent-Moore system which employs a circulating pump, a temperature recording instrument, a test stand pipe and a graduated cylinder. This system, while quite accurate, is relatively complex and bulky.
Other attemps at measuring leaks in underground tanks have been proposed and are detailed in the accompanying prior art statement. These devices, however, lack the simplicity, accuracy, portability and low cost of the present invention.
It is accordingly an object of the present invention to provide a tank-testing device which is portable, accurate and low in cost whereby underground storage tanks can be checked for leakage.
Another object of the invention is to provide a tank-testing device which is simple to operate and requires only easily obtained equipment, such as a compressed air cylinder, piping and tubing for operation.
A further object of the invention is to provide a testing device capable of magnifying changes in the level of a tank under test, whereby an accurate determination of small leaks can be made.
Other objects and advantages of the invention will be apparent from the remaining portion of the description.